- 23 Jun, 2021 1 commit
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Paolo Bonzini authored
Merge branch 'topic/ppc-kvm' of https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux into HEAD - Support for the H_RPT_INVALIDATE hypercall - Conversion of Book3S entry/exit to C - Bug fixes
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- 22 Jun, 2021 4 commits
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Nathan Chancellor authored
LLVM does not emit optimal byteswap assembly, which results in high stack usage in kvmhv_enter_nested_guest() due to the inlining of byteswap_pt_regs(). With LLVM 12.0.0: arch/powerpc/kvm/book3s_hv_nested.c:289:6: error: stack frame size of 2512 bytes in function 'kvmhv_enter_nested_guest' [-Werror,-Wframe-larger-than=] long kvmhv_enter_nested_guest(struct kvm_vcpu *vcpu) ^ 1 error generated. While this gets fixed in LLVM, mark byteswap_pt_regs() as noinline_for_stack so that it does not get inlined and break the build due to -Werror by default in arch/powerpc/. Not inlining saves approximately 800 bytes with LLVM 12.0.0: arch/powerpc/kvm/book3s_hv_nested.c:290:6: warning: stack frame size of 1728 bytes in function 'kvmhv_enter_nested_guest' [-Wframe-larger-than=] long kvmhv_enter_nested_guest(struct kvm_vcpu *vcpu) ^ 1 warning generated. Cc: stable@vger.kernel.org # v4.20+ Reported-by:kernel test robot <lkp@intel.com> Signed-off-by:
Nathan Chancellor <nathan@kernel.org> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au> Link: https://github.com/ClangBuiltLinux/linux/issues/1292 Link: https://bugs.llvm.org/show_bug.cgi?id=49610 Link: https://lore.kernel.org/r/202104031853.vDT0Qjqj-lkp@intel.com/ Link: https://gist.github.com/ba710e3703bf45043a31e2806c843ffd Link: https://lore.kernel.org/r/20210621182440.990242-1-nathan@kernel.org
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Bharata B Rao authored
In the nested KVM case, replace H_TLB_INVALIDATE by the new hcall H_RPT_INVALIDATE if available. The availability of this hcall is determined from "hcall-rpt-invalidate" string in ibm,hypertas-functions DT property. Signed-off-by:
Bharata B Rao <bharata@linux.ibm.com> Reviewed-by:
Fabiano Rosas <farosas@linux.ibm.com> Reviewed-by:
David Gibson <david@gibson.dropbear.id.au> Signed-off-by:
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Bharata B Rao authored
Now that we have H_RPT_INVALIDATE fully implemented, enable support for the same via KVM_CAP_PPC_RPT_INVALIDATE KVM capability Signed-off-by:
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Bharata B Rao authored
Enable support for process-scoped invalidations from nested guests and partition-scoped invalidations for nested guests. Process-scoped invalidations for any level of nested guests are handled by implementing H_RPT_INVALIDATE handler in the nested guest exit path in L0. Partition-scoped invalidation requests are forwarded to the right nested guest, handled there and passed down to L0 for eventual handling. Signed-off-by:
Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> [mpe: Squash in fixup patch] Signed-off-by:
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- 21 Jun, 2021 5 commits
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Sean Christopherson authored
Calculate the max VMCS index for vmcs12 by walking the array to find the actual max index. Hardcoding the index is prone to bitrot, and the calculation is only done on KVM bringup (albeit on every CPU, but there aren't _that_ many null entries in the array). Fixes: 3c0f9936 ("KVM: nVMX: Add a TSC multiplier field in VMCS12") Signed-off-by:
Sean Christopherson <seanjc@google.com> Message-Id: <20210618214658.2700765-1-seanjc@google.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
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Jim Mattson authored
As part of smaller maxphyaddr emulation, kvm needs to intercept present page faults to see if it needs to add the RSVD flag (bit 3) to the error code. However, there is no need to intercept page faults that already have the RSVD flag set. When setting up the page fault intercept, add the RSVD flag into the #PF error code mask field (but not the #PF error code match field) to skip the intercept when the RSVD flag is already set. Signed-off-by:
Jim Mattson <jmattson@google.com> Message-Id: <20210618235941.1041604-1-jmattson@google.com> Signed-off-by:
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Bharata B Rao authored
H_RPT_INVALIDATE does two types of TLB invalidations: 1. Process-scoped invalidations for guests when LPCR[GTSE]=0. This is currently not used in KVM as GTSE is not usually disabled in KVM. 2. Partition-scoped invalidations that an L1 hypervisor does on behalf of an L2 guest. This is currently handled by H_TLB_INVALIDATE hcall and this new replaces the old that. This commit enables process-scoped invalidations for L1 guests. Support for process-scoped and partition-scoped invalidations from/for nested guests will be added separately. Process scoped tlbie invalidations from L1 and nested guests need RS register for TLBIE instruction to contain both PID and LPID. This patch introduces primitives that execute tlbie instruction with both PID and LPID set in prepartion for H_RPT_INVALIDATE hcall. A description of H_RPT_INVALIDATE follows: int64 /* H_Success: Return code on successful completion */ /* H_Busy - repeat the call with the same */ /* H_Parameter, H_P2, H_P3, H_P4, H_P5 : Invalid parameters */ hcall(const uint64 H_RPT_INVALIDATE, /* Invalidate RPT translation lookaside information */ uint64 id, /* PID/LPID to invalidate */ uint64 target, /* Invalidation target */ uint64 type, /* Type of lookaside information */ uint64 pg_sizes, /* Page sizes */ uint64 start, /* Start of Effective Address (EA) range (inclusive) */ uint64 end) /* End of EA range (exclusive) */ Invalidation targets (target) ----------------------------- Core MMU 0x01 /* All virtual processors in the partition */ Core local MMU 0x02 /* Current virtual processor */ Nest MMU 0x04 /* All nest/accelerator agents in use by the partition */ A combination of the above can be specified, except core and core local. Type of translation to invalidate (type) --------------------------------------- NESTED 0x0001 /* invalidate nested guest partition-scope */ TLB 0x0002 /* Invalidate TLB */ PWC 0x0004 /* Invalidate Page Walk Cache */ PRT 0x0008 /* Invalidate caching of Process Table Entries if NESTED is clear */ PAT 0x0008 /* Invalidate caching of Partition Table Entries if NESTED is set */ A combination of the above can be specified. Page size mask (pages) ---------------------- 4K 0x01 64K 0x02 2M 0x04 1G 0x08 All sizes (-1UL) A combination of the above can be specified. All page sizes can be selected with -1. Semantics: Invalidate radix tree lookaside information matching the parameters given. * Return H_P2, H_P3 or H_P4 if target, type, or pageSizes parameters are different from the defined values. * Return H_PARAMETER if NESTED is set and pid is not a valid nested LPID allocated to this partition * Return H_P5 if (start, end) doesn't form a valid range. Start and end should be a valid Quadrant address and end > start. * Return H_NotSupported if the partition is not in running in radix translation mode. * May invalidate more translation information than requested. * If start = 0 and end = -1, set the range to cover all valid addresses. Else start and end should be aligned to 4kB (lower 11 bits clear). * If NESTED is clear, then invalidate process scoped lookaside information. Else pid specifies a nested LPID, and the invalidation is performed on nested guest partition table and nested guest partition scope real addresses. * If pid = 0 and NESTED is clear, then valid addresses are quadrant 3 and quadrant 0 spaces, Else valid addresses are quadrant 0. * Pages which are fully covered by the range are to be invalidated. Those which are partially covered are considered outside invalidation range, which allows a caller to optimally invalidate ranges that may contain mixed page sizes. * Return H_SUCCESS on success. Signed-off-by:
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Bharata B Rao authored
Add a field to mmu_psize_def to store the page size encodings of H_RPT_INVALIDATE hcall. Initialize this while scanning the radix AP encodings. This will be used when invalidating with required page size encoding in the hcall. Signed-off-by:
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Aneesh Kumar K.V authored
The type values H_RPTI_TYPE_PRT and H_RPTI_TYPE_PAT indicate invalidating the caching of process and partition scoped entries respectively. Signed-off-by:
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- 20 Jun, 2021 1 commit
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Suraj Jitindar Singh authored
The POWER9 vCPU TLB management code assumes all threads in a core share a TLB, and that TLBIEL execued by one thread will invalidate TLBs for all threads. This is not the case for SMT8 capable POWER9 and POWER10 (big core) processors, where the TLB is split between groups of threads. This results in TLB multi-hits, random data corruption, etc. Fix this by introducing cpu_first_tlb_thread_sibling etc., to determine which siblings share TLBs, and use that in the guest TLB flushing code. [npiggin@gmail.com: add changelog and comment] Signed-off-by:
Paul Mackerras <paulus@ozlabs.org> Signed-off-by:
Nicholas Piggin <npiggin@gmail.com> Reviewed-by:
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- 18 Jun, 2021 8 commits
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David Matlack authored
The root_hpa checks below the top-level check in kvm_mmu_page_fault are theoretically redundant since there is no longer a way for the root_hpa to be reset during a page fault. The details of why are described in commit ddce6208 ("KVM: x86/mmu: Move root_hpa validity checks to top of page fault handler") __direct_map, kvm_tdp_mmu_map, and get_mmio_spte are all only reachable through kvm_mmu_page_fault, therefore their root_hpa checks are redundant. Suggested-by:
David Matlack <dmatlack@google.com> Message-Id: <20210617231948.2591431-5-dmatlack@google.com> Signed-off-by:
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David Matlack authored
This change simplifies the call sites slightly and also abstracts away the implementation detail of looking at root_hpa as the mechanism for determining if the mmu is the TDP MMU. Suggested-by:
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David Matlack authored
This check is redundant because the root shadow page will only be a TDP MMU page if is_tdp_mmu_enabled() returns true, and is_tdp_mmu_enabled() never changes for the lifetime of a VM. It's possible that this check was added for performance reasons but it is unlikely that it is useful in practice since to_shadow_page() is cheap. That being said, this patch also caches the return value of is_tdp_mmu_root() in direct_page_fault() since there's no reason to duplicate the call so many times, so performance is not a concern. Suggested-by:
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David Matlack authored
The check for is_tdp_mmu_root in kvm_tdp_mmu_map is redundant because kvm_tdp_mmu_map's only caller (direct_page_fault) already checks is_tdp_mmu_root. Suggested-by:
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Paolo Bonzini authored
If is_tdp_mmu_root is not inlined, the elimination of TDP MMU calls as dead code might not work out. To avoid this, explicitly declare the stubbed is_tdp_mmu_root on 32-bit hosts. Signed-off-by: -
Sean Christopherson authored
WARN if NX is reported as supported but not enabled in EFER. All flavors of the kernel, including non-PAE 32-bit kernels, set EFER.NX=1 if NX is supported, even if NX usage is disable via kernel command line. KVM relies on NX being enabled if it's supported, e.g. KVM will generate illegal NPT entries if nx_huge_pages is enabled and NX is supported but not enabled. Signed-off-by:
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Sean Christopherson authored
Refuse to load KVM if NX support is not available. Shadow paging has assumed NX support since commit 9167ab79 ("KVM: vmx, svm: always run with EFER.NXE=1 when shadow paging is active"), and NPT has assumed NX support since commit b8e8c830 ("kvm: mmu: ITLB_MULTIHIT mitigation"). While the NX huge pages mitigation should not be enabled by default for AMD CPUs, it can be turned on by userspace at will. Unlike Intel CPUs, AMD does not provide a way for firmware to disable NX support, and Linux always sets EFER.NX=1 if it is supported. Given that it's extremely unlikely that a CPU supports NPT but not NX, making NX a formal requirement is far simpler than adding requirements to the mitigation flow. Fixes: 9167ab79 ("KVM: vmx, svm: always run with EFER.NXE=1 when shadow paging is active") Fixes: b8e8c830 ("kvm: mmu: ITLB_MULTIHIT mitigation") Signed-off-by:
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Sean Christopherson authored
Refuse to load KVM if NX support is not available and EPT is not enabled. Shadow paging has assumed NX support since commit 9167ab79 ("KVM: vmx, svm: always run with EFER.NXE=1 when shadow paging is active"), so for all intents and purposes this has been a de facto requirement for over a year. Do not require NX support if EPT is enabled purely because Intel CPUs let firmware disable NX support via MSR_IA32_MISC_ENABLES. If not for that, VMX (and KVM as a whole) could require NX support with minimal risk to breaking userspace. Fixes: 9167ab79 ("KVM: vmx, svm: always run with EFER.NXE=1 when shadow paging is active") Signed-off-by:
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- 17 Jun, 2021 21 commits
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Kai Huang authored
TDP MMU iterator's level is identical to page table's actual level. For instance, for the last level page table (whose entry points to one 4K page), iter->level is 1 (PG_LEVEL_4K), and in case of 5 level paging, the iter->level is mmu->shadow_root_level, which is 5. However, struct kvm_mmu_page's level currently is not set correctly when it is allocated in kvm_tdp_mmu_map(). When iterator hits non-present SPTE and needs to allocate a new child page table, currently iter->level, which is the level of the page table where the non-present SPTE belongs to, is used. This results in struct kvm_mmu_page's level always having its parent's level (excpet root table's level, which is initialized explicitly using mmu->shadow_root_level). This is kinda wrong, and not consistent with existing non TDP MMU code. Fortuantely sp->role.level is only used in handle_removed_tdp_mmu_page() and kvm_tdp_mmu_zap_sp(), and they are already aware of this and behave correctly. However to make it consistent with legacy MMU code (and fix the issue that both root page table and its child page table have shadow_root_level), use iter->level - 1 in kvm_tdp_mmu_map(), and change handle_removed_tdp_mmu_page() and kvm_tdp_mmu_zap_sp() accordingly. Reviewed-by:
Ben Gardon <bgardon@google.com> Signed-off-by:
Kai Huang <kai.huang@intel.com> Message-Id: <bcb6569b6e96cb78aaa7b50640e6e6b53291a74e.1623717884.git.kai.huang@intel.com> Signed-off-by:
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Kai Huang authored
Currently pf_fixed is not increased when prefault is true. This is not correct, since prefault here really means "async page fault completed". In that case, the original page fault from the guest was morphed into as async page fault and pf_fixed was not increased. So when prefault indicates async page fault is completed, pf_fixed should be increased. Additionally, currently pf_fixed is also increased even when page fault is spurious, while legacy MMU increases pf_fixed when page fault returns RET_PF_EMULATE or RET_PF_FIXED. To fix above two issues, change to increase pf_fixed when return value is not RET_PF_SPURIOUS (RET_PF_RETRY has already been ruled out by reaching here). More information: https://lore.kernel.org/kvm/cover.1620200410.git.kai.huang@intel.com/T/#mbb5f8083e58a2cd262231512b9211cbe70fc3bd5 Fixes: bb18842e ("kvm: x86/mmu: Add TDP MMU PF handler") Reviewed-by:
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Kai Huang authored
Currently tdp_mmu_map_handle_target_level() returns 0, which is RET_PF_RETRY, when page fault is actually fixed. This makes kvm_tdp_mmu_map() also return RET_PF_RETRY in this case, instead of RET_PF_FIXED. Fix by initializing ret to RET_PF_FIXED. Note that kvm_mmu_page_fault() resumes guest on both RET_PF_RETRY and RET_PF_FIXED, which means in practice returning the two won't make difference, so this fix alone won't be necessary for stable tree. Fixes: bb18842e ("kvm: x86/mmu: Add TDP MMU PF handler") Reviewed-by:
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Wanpeng Li authored
KVM_GET_LAPIC stores the current value of TMCCT and KVM_SET_LAPIC's memcpy stores it in vcpu->arch.apic->regs, KVM_SET_LAPIC could store zero in vcpu->arch.apic->regs after it uses it, and then the stored value would always be zero. In addition, the TMCCT is always computed on-demand and never directly readable. Suggested-by:
Wanpeng Li <wanpengli@tencent.com> Message-Id: <1623223000-18116-1-git-send-email-wanpengli@tencent.com> Signed-off-by:
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Ashish Kalra authored
This hypercall is used by the SEV guest to notify a change in the page encryption status to the hypervisor. The hypercall should be invoked only when the encryption attribute is changed from encrypted -> decrypted and vice versa. By default all guest pages are considered encrypted. The hypercall exits to userspace to manage the guest shared regions and integrate with the userspace VMM's migration code. Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Joerg Roedel <joro@8bytes.org> Cc: Borislav Petkov <bp@suse.de> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: x86@kernel.org Cc: kvm@vger.kernel.org Cc: linux-kernel@vger.kernel.org Reviewed-by:
Steve Rutherford <srutherford@google.com> Signed-off-by:
Brijesh Singh <brijesh.singh@amd.com> Signed-off-by:
Ashish Kalra <ashish.kalra@amd.com> Co-developed-by:
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Paolo Bonzini authored
Make them the same type as vCPU stats. There is no reason to limit the counters to unsigned long. Signed-off-by: -
Sean Christopherson authored
Snapshot kvm->stats.nx_lpage_splits into a local unsigned long to avoid 64-bit division on 32-bit kernels. Casting to an unsigned long is safe because the maximum number of shadow pages, n_max_mmu_pages, is also an unsigned long, i.e. KVM will start recycling shadow pages before the number of splits can exceed a 32-bit value. ERROR: modpost: "__udivdi3" [arch/x86/kvm/kvm.ko] undefined! Fixes: 7ee093d4f3f5 ("KVM: switch per-VM stats to u64") Signed-off-by: -
Vitaly Kuznetsov authored
When APICv is active, interrupt injection doesn't raise KVM_REQ_EVENT request (see __apic_accept_irq()) as the required work is done by hardware. In case KVM_REQ_APICV_UPDATE collides with such injection, the interrupt may never get delivered. Currently, the described situation is hardly possible: all kvm_request_apicv_update() calls normally happen upon VM creation when no interrupts are pending. We are, however, going to move unconditional kvm_request_apicv_update() call from kvm_hv_activate_synic() to synic_update_vector() and without this fix 'hyperv_connections' test from kvm-unit-tests gets stuck on IPI delivery attempt right after configuring a SynIC route which triggers APICv disablement. Signed-off-by:
Vitaly Kuznetsov <vkuznets@redhat.com> Message-Id: <20210609150911.1471882c-4-vkuznets@redhat.com> Signed-off-by:
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Sean Christopherson authored
Drop the explicit check on EPTP switching being enabled. The EPTP switching check is handled in the generic VMFUNC function check, while the underlying VMFUNC enablement check is done by hardware and redone by generic VMFUNC emulation. The vmcs12 EPT check is handled by KVM at VM-Enter in the form of a consistency check, keep it but add a WARN. Signed-off-by:
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Sean Christopherson authored
WARN and inject #UD when emulating VMFUNC for L2 if the function is out-of-bounds or if VMFUNC is not enabled in vmcs12. Neither condition should occur in practice, as the CPU is supposed to prioritize the #UD over VM-Exit for out-of-bounds input and KVM is supposed to enable VMFUNC in vmcs02 if and only if it's enabled in vmcs12, but neither of those dependencies is obvious. Signed-off-by:
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Sean Christopherson authored
Remove the @reset_roots param from kvm_init_mmu(), the one user, kvm_mmu_reset_context() has already unloaded the MMU and thus freed and invalidated all roots. This also happens to be why the reset_roots=true paths doesn't leak roots; they're already invalid. No functional change intended. Signed-off-by:
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Sean Christopherson authored
Defer the MMU sync on PCID invalidation so that multiple sync requests in a single VM-Exit are batched. This is a very minor optimization as checking for unsync'd children is quite cheap. Signed-off-by:
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Sean Christopherson authored
Use __kvm_mmu_new_pgd() via kvm_init_shadow_ept_mmu() to emulate VMFUNC[EPTP_SWITCH] instead of nuking all MMUs. EPTP_SWITCH is the EPT equivalent of MOV to CR3, i.e. is a perfect fit for the common PGD flow, the only hiccup being that A/D enabling is buried in the EPTP. But, that is easily handled by bouncing through kvm_init_shadow_ept_mmu(). Explicitly request a guest TLB flush if VPID is disabled. Per Intel's SDM, if VPID is disabled, "an EPTP-switching VMFUNC invalidates combined mappings associated with VPID 0000H (for all PCIDs and for all EP4TA values, where EP4TA is the value of bits 51:12 of EPTP)". Note, this technically is a very bizarre bug fix of sorts if L2 is using PAE paging, as avoiding the full MMU reload also avoids incorrectly reloading the PDPTEs, which the SDM explicitly states are not touched: If PAE paging is in use, an EPTP-switching VMFUNC does not load the four page-directory-pointer-table entries (PDPTEs) from the guest-physical address in CR3. The logical processor continues to use the four guest-physical addresses already present in the PDPTEs. The guest-physical address in CR3 is not translated through the new EPT paging structures (until some operation that would load the PDPTEs). In addition to optimizing L2's MMU shenanigans, avoiding the full reload also optimizes L1's MMU as KVM_REQ_MMU_RELOAD wipes out all roots in both root_mmu and guest_mmu. Signed-off-by:
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Sean Christopherson authored
Use KVM_REQ_TLB_FLUSH_GUEST instead of KVM_REQ_MMU_RELOAD when emulating INVPCID of all contexts. In the current code, this is a glorified nop as TLB_FLUSH_GUEST becomes kvm_mmu_unload(), same as MMU_RELOAD, when TDP is disabled, which is the only time INVPCID is only intercepted+emulated. In the future, reusing TLB_FLUSH_GUEST will simplify optimizing paths that emulate a guest TLB flush, e.g. by synchronizing as needed instead of completely unloading all MMUs. Signed-off-by:
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Sean Christopherson authored
When emulating INVVPID for L1, free only L2+ roots, using the guest_mode tag in the MMU role to identify L2+ roots. From L1's perspective, its own TLB entries use VPID=0, and INVVPID is not requied to invalidate such entries. Per Intel's SDM, INVVPID _may_ invalidate entries with VPID=0, but it is not required to do so. Cc: Lai Jiangshan <laijs@linux.alibaba.com> Signed-off-by:
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Sean Christopherson authored
Drop the dedicated nested_vmx_transition_mmu_sync() now that the MMU sync is handled via KVM_REQ_TLB_FLUSH_GUEST, and fold that flush into the all-encompassing nested_vmx_transition_tlb_flush(). Opportunistically add a comment explaning why nested EPT never needs to sync the MMU on VM-Enter. Signed-off-by:
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Sean Christopherson authored
Drop skip_mmu_sync and skip_tlb_flush from __kvm_mmu_new_pgd() now that all call sites unconditionally skip both the sync and flush. No functional change intended. Signed-off-by:
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Sean Christopherson authored
Introduce nested_svm_transition_tlb_flush() and use it force an MMU sync and TLB flush on nSVM VM-Enter and VM-Exit instead of sneaking the logic into the __kvm_mmu_new_pgd() call sites. Add a partial todo list to document issues that need to be addressed before the unconditional sync and flush can be modified to look more like nVMX's logic. In addition to making nSVM's forced flushing more overt (guess who keeps losing track of it), the new helper brings further convergence between nSVM and nVMX, and also sets the stage for dropping the "skip" params from __kvm_mmu_new_pgd(). Cc: Maxim Levitsky <mlevitsk@redhat.com> Signed-off-by:
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Sean Christopherson authored
Stop leveraging the MMU sync and TLB flush requested by the fast PGD switch helper now that kvm_set_cr3() manually handles the necessary sync, frees, and TLB flush. This will allow dropping the params from the fast PGD helpers since nested SVM is now the odd blob out. Signed-off-by:
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Sean Christopherson authored
Flush and sync all PGDs for the current/target PCID on MOV CR3 with a TLB flush, i.e. without PCID_NOFLUSH set. Paraphrasing Intel's SDM regarding the behavior of MOV to CR3: - If CR4.PCIDE = 0, invalidates all TLB entries associated with PCID 000H and all entries in all paging-structure caches associated with PCID 000H. - If CR4.PCIDE = 1 and NOFLUSH=0, invalidates all TLB entries associated with the PCID specified in bits 11:0, and all entries in all paging-structure caches associated with that PCID. It is not required to invalidate entries in the TLBs and paging-structure caches that are associated with other PCIDs. - If CR4.PCIDE=1 and NOFLUSH=1, is not required to invalidate any TLB entries or entries in paging-structure caches. Extract and reuse the logic for INVPCID(single) which is effectively the same flow and works even if CR4.PCIDE=0, as the current PCID will be '0' in that case, thus honoring the requirement of flushing PCID=0. Continue passing skip_tlb_flush to kvm_mmu_new_pgd() even though it _should_ be redundant; the clean up will be done in a future patch. The overhead of an unnecessary nop sync is minimal (especially compared to the actual sync), and the TLB flush is handled via request. Avoiding the the negligible overhead is not worth the risk of breaking kernels that backport the fix. Fixes: 956bf353 ("kvm: x86: Skip shadow page resync on CR3 switch when indicated by guest") Cc: Junaid Shahid <junaids@google.com> Signed-off-by: -
Sean Christopherson authored
Drop bogus logic that incorrectly clobbers the accessed/dirty enabling status of the nested MMU on an EPTP switch. When nested EPT is enabled, walk_mmu points at L2's _legacy_ page tables, not L1's EPT for L2. This is likely a benign bug, as mmu->ept_ad is never consumed (since the MMU is not a nested EPT MMU), and stuffing mmu_role.base.ad_disabled will never propagate into future shadow pages since the nested MMU isn't used to map anything, just to walk L2's page tables. Note, KVM also does a full MMU reload, i.e. the guest_mmu will be recreated using the new EPTP, and thus any change in A/D enabling will be properly recognized in the relevant MMU. Fixes: 41ab9372 ("KVM: nVMX: Emulate EPTP switching for the L1 hypervisor") Signed-off-by:
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